Russian Hacker Suspected in Massive LinkedIn Breach Arrested Overseas

A suspected Russian hacker has been arrested in the Czech Republic for his alleged role in a cyber-attack on social media giant LinkedIn, sources told ABC News.

The man, so far unidentified by U.S. authorities, was taken into custody by Czech National Police in Prague, based on a "red notice" issued by Interpol, the FBI said in a statement.

While the FBI has not confirmed the alleged hacker's ties to the LinkedIn breach, the agency's statement said he is "suspected of conducting criminal activities targeting U.S. interests."

In May, LinkedIn announced it "was the victim of an unauthorized access" four years earlier that exposed email addresses and passwords of more than 100 million users -- which were reportedly offered for sale on the so-called "dark web."

"We are thankful for the hard work and dedication of the FBI in its efforts to locate and capture the parties believed to be responsible for this criminal activity," LinkedIn said in a statement.

The 27-year-old suspect was arrested two weeks ago in the restaurant of a Prague hotel, sources told ABC News. During the arrest, they said, he collapsed and was then taken to a nearby hospital.

U.S. prosecutors are asking Czech authorities to extradite him to the U.S. so he can face federal charges in San Francisco.

The Russian government said it will try to block the extradition, amid growing tensions between the United States and Russia over cyber-attacks on U.S. targets that the government believes originate in Russia.

"We don't accept U.S. policy of imposing its extraterritorial jurisdiction on all countries," Alexei Vladimirovich Kolmakov, a spokesman with the Russian Embassy in Prague, told ABC News. "We insist that the detained Russian citizen is transferred to Russia."

In its statement, the FBI vowed to go after hackers wherever they may be.

"As cyber crime can originate anywhere in the world, international cooperation is crucial to successfully defeat cyber adversaries," the statement said.

The arrest in Prague comes only days after U.S. authorities made a rare public accusation, blaming the Russian government for an onslaught of cyber-attacks on Americans political targets including the Democratic National Committee. Sources have also blamed Russian hackers for targeting voter-related systems in nearly half of the U.S. states.

As ABC News first reported, hackers were able to successfully access voter-related information in four states by targeting not only government systems, but also by breaking into computers associated with private contractors hired to handle voter information.